package com.bdqn;


import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Map;

public class SimpleBeanConvertor {
    private static Logger logger= LogManager.getLogger(SimpleBeanConvertor.class);
    /**
     *将HTTP请求中的参数赋值给指定类型JavaBean的相关属性
     *
     */
    public static <T>T convert(HttpServletRequest request,Class<T>targetType) throws IllegalAccessException, InstantiationException, ParseException, InvocationTargetException, NoSuchMethodException, ClassNotFoundException {
        Map<String,String[]> params=request.getParameterMap();
        if(params.size()==0)return null;
        T target=targetType.newInstance();//创建JavaBean实例
        //获取JavaBean中所以方法
        Method [] allMethods=targetType.getMethods();
        if(allMethods!=null && allMethods.length>0){
            for (Method method:allMethods){
                if(method.getName().startsWith("set")){
                    Class [] args=method.getParameterTypes();
                    if(args.length==1){
                        //获取set方法对应的请求参数:setName→name
                        String paramName=method.getName().substring(3,4).toLowerCase()+method.getName().substring(4);
                        if(params.containsKey(paramName)){
                            try {
                                Object value=parseValue(params.get(paramName),args[0]);
                                method.invoke(target,value);
                            }catch (ParseException e){
                                logger.debug("参数转换错误",e);
                                e.printStackTrace();
                                throw e;
                            }
                        }else if(Boolean.class==args[0]||boolean.class==args[0]){
                            //如果是boolean,不存在表示false
                            method.invoke(target,false);
                        }
                    }
                }
            }
        }
        return target;
    }

    public static Object parseValue(String[] value,Class type) throws ParseException, ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
        if(String.class==type)
            return value[0];
        if(java.util.Date.class==type)
            return new SimpleDateFormat("yyyy-MM-dd").parse(value[0]);
        if(boolean.class==type||Boolean.class==type)
            return true;
        if(char.class==type||Character.class==type)
            return value[0].charAt(0);
        if(int.class==type||byte.class==type||long.class==type||float.class==type||double.class==type)
            try {
                type=Class.forName("java.lang."+type.getName().substring(0,1).toUpperCase()+type.getName().substring(1));
            }catch (ClassNotFoundException e){
                e.printStackTrace();
            }
        if(type.getName().startsWith("java.lang.")||type.getName().startsWith("java.math."))
            try {
                return type.getConstructor(String.class).newInstance(value[0]);
            }catch (Exception e){
                e.printStackTrace();
            }
        if(short.class==type||byte.class==type||long.class==type||float.class==type||double.class==type)
            type = Class.forName("java.lang." + type.getName().substring(0,1).toUpperCase() + type.getName().substring(1));
        if (type.getName().startsWith("java.lang.") || type.getName().startsWith("java.math."))
            return type.getConstructor(String.class).newInstance(value[0]);
        return false;
    }
}